Services delivered by providers of networked application services, by their nature, span a variety of provider and customer owned and managed infrastructures. For example, the application services begin at a provider or customer owned hosting platform within a provider or customer owned data center infrastructure, travel across one or more wide-area networks (WANs) owned and managed by one or more service providers and across one or more customer owned WAN and LAN infrastructures, before reaching a customer-owned desktop or mobile computing platform.
In order to provide the most effective service, it is often required that a network application service providers keep track of the delay within the network. Typically, network delay is measured based upon a transaction oriented measurement methodology. For example, a total delay is measured from the time a request is transmitted from a client until the last portion of the response is received back from a server. The total delay includes a server delay and a network delay.
The server delay corresponds to the time a request is received by the server until the time the server begins to transmit the last portion of the response back to the client. Conventionally, the network delay is the difference between the total delay and the server delay. The problem with using a transaction oriented measurement scheme is that the network delay may have a high magnitude in some instances where there are no problems with the network.
For instance, there may be a first transaction where the total delay is sixty-five seconds, where five seconds (of the sixty-five seconds) are attributed to server delay (e.g., time required to begin transmission of one megabit file). In such an instance, the network delay would be sixty seconds. A second transaction may also have a sixty-five second delay. In the second transaction, the server delay may again be five seconds, and the network delay sixty seconds. However, in this transaction, the server transmitted a 100 Kb file ten times due to retransmissions, thus accounting for the 60 second network delay. Both the first and second transactions have the same values for the total, server and network delays, even though there are no abnormalities with the first transaction and severe network problems during the second transaction. Therefore, what is desired is a more accurate method for measuring network delay.